If the RHEL installation is licensed then this is not difficult at all. You just need to run

# yum install tigervnc-server -yat a terminal. However this gets complicated when the installation of RHEL is not licensed.After a considerable number of disappointing hours of searching, testing, and some research I finally found a solution to this. Here I am going to use TigerVNC as the VNC server and RealVNC viewer as the client (you can use any VNC viewer you prefer).1. Navigate to the TigerVNC downloads which at the moment of this blog post is hosted as a SourceForgeproject here and download the latest build corresponding to the bit version of your linux installation.2. Extract the contents into a suitable location.3. Within the extracted contents a folder named bin exists and it contains all the binaries required for the sound operation of VNC server (except the one which as they say is obsolete now). Locate this folder and copy the contents of it to /bin directory in linux. The following files need to be copied.

vncconfig

vncpasswd

vncserver

Xvnc

4. Execute the command vncsever at a terminal.# vncserver

This will require you to set a password for logging in via VNC remotely.

This will also create the necessary files required to start a xsession for a particular user when logging in via VNC.

5. Usually after the above step you are good to go but in some cases you might end up with an error Connection timed out(1006) at the VNC viewer when you try to log in. This is because the host in which the VNC server runs is blocking the VNC communication, i.e. it's blocking the VNC port-5900. Here you have to allow the port 5900 at the firewall as a trusted port or if security is not a big issue with the Red Hat host then you can simply disable it.